1. Field of the Invention
The present invention relates to a cassette for accommodating a material in the form of a tape wound on a reel, such as an electrophotographic film, which needs to be grounded. More particularly, the present invention pertains to a cassette for accommodating an electrically conductive film or other similar materials which includes a reel provided with a contact piece for grounding.
2. Description of the Related Art
Electrophotographic film, when applied to, for example, a document storage and retrieval system, provides various advantages which cannot practically be obtained from conventional films made of a silver halide photosensitive material, as is described in the specification of Japanese Patent Laid-Open No. 79234/1984. Electrophotographic film is expected to become more practically utilizable by accommodating it in a cassette which will facilitate its management, storage and handling.
This electrophotographic film is formed from a transparent base in the form of a tape which includes, for example, polyester as its principal component, together with a transparent electrically conductive layer and a transparent photoconductive insulating layer which are, in that order, coated on the base, the electrically conductive layer needing to be grounded when, for example, it is electrically charged.
It may be considered reasonable to assume that electrophotographic film accommodated in a cassette is grounded through the reel on which the film is wound.
In general, it is advantageous to employ a reel molded from a synthetic resin from the viewpoint of attaining reduction in costs and weight. However, it is not possible to obtain any electrical connection between the electrophotographic film and the synthetic resin reel solely by winding the film on the reel.